A cache (also referred to as a high-speed cache memory) is located between a central processing unit (CPU) and a memory and is primarily used to solve a problem of mismatch between a speed of CPU operation and a speed of memory read/write. Currently, a computer uses at most a three-level cache, where a high-speed small-capacity cache is used at level 1 cache (L1 cache), a medium-speed larger-capacity cache is used at level 2 cache (L2 cache), and a low-speed large-capacity cache is used at level 3 cache (L3 cache).
Based on the multi-level cache, a specific process of executing a read operation by a CPU in the prior art is as follows.
When a CPU core sends a data read request, a level-by-level search manner is applied. That is, data search begins in the L1 cache first; if there is no searching data in the L1 cache (cache miss), a search is performed in the L2 cache, and so on, until data is searched out.
In the foregoing process, the cache is generally hit after the search is performed multiple times. For example, assuming that data on which a read operation is to be performed is stored in the L3 cache, a data search is performed in the L3 cache only when both the L1 cache and the L2 cache are missed, which leads to low efficiency of cache access.